The invention relates to a fastener capable of clamping members, which are to be clamped and are spaced a certain spacing from each other, while maintaining a clearance therebetween and absorbing some possible scatter in the spacing or some possible axial deviation.
U.S. Pat. No. 5,288,191 for Edvald Rucker et al discloses a conventional fastener of the same kind as described above, which fastener involves a high manufacturing cost since it is composed of many constituent elements and a part of the elements is special in shape. Further, since forces required for movements of the constituent elements for holding of a predetermined spacing rely on a pushing force of and torque of a bolt-like member inserted into the constituent elements under frictions, an operator for performing clamping of the fastener is required to rotate the bolt-like member while applying a pushing force, so that handling of the fastener is complicated. In addition, since the fastener has no positive loosening preventive function, application of the fastener has been difficult under circumstances under much vibrations.
The invention has been devised in order to solve the above-mentioned problem of prior fasteners, and this problem can be solved by a fastener for members (M1, M2) to be clamped with a certain spacing therebetween, the fastener comprising a nut (10) having one end surface of a substantially cylindrical-shaped main body adapted to be latched by one (M1) of the members to be clamped, the nut being formed on an inner peripheral surface thereof with a first thread (13) comprising an internal thread capable of threading onto a thread of a bolt (40) and a second thread (14) comprising aninternal thread inverse to thread ridges of the thread of the bolt and capable of threading onto a first thread (21) of a movable collar (20) comprising an external thread, which is formed on an outer peripheral surface of a substantially cylindrical-shaped main body of the movable collar (20) and is inverse to thread ridges of the thread of the bolt; the movable collar (20) having in an inner bore thereof a torque transmitting means capable of transmitting torque of the bolt, which is inserted axially into the inner bore, to the movable collar through threadxe2x80x94thread engagement; and the bolt (40) having a shank (42), on an outer peripheral surface of which is formed a thread comprising an external thread capable of threading into the first thread (13) of the nut; and wherein a portion of the thread of the bolt comprises special thread ridges (422), by which a frictional force greater than that obtained in engagement between normal threads is imparted to the threadxe2x80x94thread engagement.